I passed on deadreckoning myself , but it is a per project and game play style. I don't think Robombs would need it. Since blowing people up are done with stationary objects. Where as shooting people with bullets or missiles would be a different story. Since I don't know his game. I'm only suggesting to go with standard practices in regards to highly shooting orientated games.

Robombs sends every 30ms if possible. I've never noticed a problem with entities moving in directions in which they shouldn't unless the lag is really bad. All the bots are running on a separate client too, which uses the same time interval to synchronize with the server and the other clients (including the local one) and that works fine...

Well I don't mean my objects move in the wrong direction but you can see like stuttering/rubber band type thing (very small, but noticeable) if an object is say for example running in changing circles/curves (not sure if its a problem in a constant circle) as opposed to a straight line. That site jayderu linked, the first 2 choices on there are basically what I have tried (kind of combination of the two, i send the points each time and then use the velocity in between to keep the object moving in the same direction). However, that site basically says they both suck and to use cubic splines. Before that, though, I'm just gonna try to send the positions faster than 50 ms, since u said u do 30ms and thats almost double as fast as 50ms.